One of the main characteristics of a diamond is light return or light performance, i.e., the amount of light returned to the eye from the diamond. The higher the light performance grade, the greater the brilliance (white light) and fire (colored light) of the diamond. Light performance is impacted by, among other things, the number, shape, angles and arrangement of the facets on the cut diamond. However, just increasing or decreasing the number and angle of the facets does not directly correlate to an increase in light performance. In fact, sometimes an increase in the number of facets can result in a diamond that is dull and lifeless, exactly the opposite of what is desired. It is the exact and precise combination of angles and facets that have to come together to create the perfect formula for the highest light return.
The cushion cut diamond is a diamond shape that was popular in the early 19th century and was so named because it was very similar to a plump cushion or pillow. The forerunner to the cushion-cut is the so-called Old Mine Cut, which was a square cut with rounded corners, deeply cut with a high crown, small table and large facets. The Old Mine Cut had 33 crown and 25 pavilion facets.
Many of the most famous gemstones in the world are cushion-cuts, including the blue Hope Diamond (45.52 cts), the Regent Diamond (140.5 cts) and the yellow Tiffany Diamond (128.54 cts). The largest cut blue sapphire in the world, the 423 ct Logan Sapphire in the Smithsonian Museum of Natural History, is a cushion-cut.
The cushion cut diamond has gained in popularity in recent years as a more distinctive alternative to the traditional round brilliant cut. Typical cushion-cut diamonds contain from 58 to 64 facets. However, even with this number of facets, compared to round brilliant cut diamonds, typical cushion cut diamonds available to consumers lack both fire and brilliance.